Most Robust Cast Iron Atmospheric Boilers

D107

If one decides to forego a mod con and opt for a gas CI with Outdoor Reset for a small 40K btu house, which of today's brands/models do you recommend? We've heard that these days even CI units are not made the same as before, with thinner heat exchangers, etc. I would be looking for the ones with the thickest heat exchangers, best parts longevity and long-term availability, ease of maintenance, best warranty, etc. My mother has a 2006 Buderus oil G115-3 that, once they added the tiger loop and got the right nozzle has worked trouble-free for 12 years and looks like it could go for another 20. Not sure I'd use an ECM circ here due to hard water issues and some old 1-inch steel gravity riser pipes mixed with the 3/4" copper run.

GBart

I don't rec'd any atmospheric gas especially dry base boilers, even with outdoor reset you're only @ 50% actual efficiency.

It's 2018, Weil McLain cast iron with a Carlin EZ gas burner would be an excellent choice if CI is what you want. I don't think they offer it and I'm not sure why, it seems a lot of if not all of the gas cast iron boilers are dry base and dry base is garbage 1940's technology in oil or gas.

We've experimented with the Weil McLain cast iron wet base and Carlin EZ gas burners and found they run great, in fact, I haven't found one oil fired unit that doesn't run great with the EZ gas.

Steamhead

GBart said:

I don't rec'd any atmospheric gas especially dry base boilers, even with outdoor reset you're only @ 50% actual efficiency.

Where did you get this? Is there any supporting documentation?

D107

@GBart Well that Buderus G115 is a wetbase triple pass which is the type of CI boiler i think I was looking for, 86% eff. Not sure why you assumed dry base.

Noel

86% burning oil at 140°, 83% burning gas with a Riello gas burner. I don't have numbers on any other gas burners, it wasn't tested with them.
Noel

rick in Alaska

You might want to check out the Weil McLain GV90+ boiler. It is the old school cast iron boiler that has been around forever, and is quite reliable and simple, but then they added a secondary heat exchanger on it to make it a condensing unit. In my limited opinion on it, the worst thing about it is it has a long footprint to it. The best part; It has been around a long time and parts are available.
Rick

Steamhead

I agree that wet-base/power burner is the way to go for non-condensing gas. However, some hot-water atmospherics have gotten good enough that wet-base/power burner is a tough sell in the smaller sizes, due to its higher cost. The Burnham ES-2 and 3 series boilers are two examples.

GBart

Steamhead said:

GBart said:

I don't rec'd any atmospheric gas especially dry base boilers, even with outdoor reset you're only @ 50% actual efficiency.

Where did you get this? Is there any supporting documentation?

dry base = poor efficiency, atmospheric is a joke, talking real efficiency not AFUE, AFUE has been proven to be completely false

GBart

Another good reason to dump dry base boilers, you'll never have a base burn out and fire from a wet base.

" Boiler Types

Two types of boilers are on the market today: dry base and wet base. The type of boiler is significant for the fire investigator for the following reasons.

Wet base boiler. In a full wet base boiler, the boiler water jacket assembly surrounds the entire combustion chamber on five sides--top, bottom, back, right, and left. The heat shield is in the lower portion of the boiler, in front of the combustion chamber to which the oil burner is connected.

Dry base boiler. On a dry base boiler, the entire bottom portion of the boiler surrounding the combustion chamber is a steel outer shell and has an insulating refractory material lining inside the combustion chamber.

Some fires result from a base burnout, usually the result of a lack of proper maintenance or an overfiring in the combustion chamber. When the base of a dry boiler burns out, the heat and products--heat, smoke, and soot--from the combustion chamber are expelled from the bottom side or back of the boiler instead of traveling up through the boiler`s vertical flue passages. If the boiler is in a room with a wood-combustible wall or if other combustibles are surrounding the boiler, these items can be ignited and cause a fire.

* During the postfire investigation, remove the boiler`s outer jacket assembly and examine the areas surrounding the combustion chamber. This type of base burnout cannot occur if the boiler has a full wet base."

from- https://www.fireengineering.com/articles/print/volume-152/issue-1/features/investigation-of-heating-equipment.html

GBart

and regarding AFUE

" When the government created AFUE (Annual Fuel Utilization Efficiency) ratings, they had a good plan. They intended to help consumers understand differences in the efficiency of heating systems with a rating system that showed the percentage of fuel that is used to heat a home.

However, AFUE ratings don’t help consumers make educated decisions about a hot water heating system’s efficiency because it only measures some chimney related losses. It’s like saying highway driving is the miles per gallon you’ll get all year when you know you’ll be doing most of your driving around town. Recent U.S. Department of Energy lab results identify AFUE as a rating system that lets consumers and heating professionals down."

from - http://energykinetics.com/afue/

Robert O'Brien

Buderus GC144 is very nice in a CI boiler and you seem to have some Buderus experience. Very easy wireless ODR option

D107

@Robert O'Brien Thanks yes, I've been looking at that or the GA-124/17, which has sealed combustion. Or GC-124? GC-124II? Model numbers confusing. For the GC144 I think I'd have to have fan-in-a-can to avoid negative boiler room pressure. If I understand the GA-124 correctly, I'd get direct air intake to burner by pipe and could either vent through SS chimney liner or sidewall vent. The GA net output is a bit closer to my heat loss of 40K. (likely really only 30K).

Two people sometimes taking back to back showers; currently using a stand-alone 50 gallon gas hwh firing at 30K btu never run out of water--don't know what that converts to for indirect btu firing requirement.

Love the idea of stacking indirect above the boiler OR using a turbo-max as combo indirect and buffer tank to avoid short cycling.

Read about something called the GA-124x but not sure what that is.

Like to know how long Buderus will stock parts for this and if heat exchanger is thick and durable. As I mentioned our water is hard (not extremely so). Currently with 36 year old WM which is holding up very well.

Robert O'Brien

All residential Buderus models except GC144 are discontinued.

Steamhead

GBart said:

Steamhead said:

GBart said:

I don't rec'd any atmospheric gas especially dry base boilers, even with outdoor reset you're only @ 50% actual efficiency.

Where did you get this? Is there any supporting documentation?

dry base = poor efficiency, atmospheric is a joke, talking real efficiency not AFUE, AFUE has been proven to be completely false

As long as everything in a certain class of boilers is tested the same way, it at least provides a way to compare boilers of a given size and type.

Robert O'Brien

Steamhead said:

GBart said:

Steamhead said:

GBart said:

I don't rec'd any atmospheric gas especially dry base boilers, even with outdoor reset you're only @ 50% actual efficiency.

Where did you get this? Is there any supporting documentation?

dry base = poor efficiency, atmospheric is a joke, talking real efficiency not AFUE, AFUE has been proven to be completely false

As long as everything in a certain class of boilers is tested the same way, it at least provides a way to compare boilers of a given size and type.

It does within the confines of the test parameters. Where it really goes wrong is when DHW enters the picture.

The Steam Whisperer

If you are looking for a real basic cast iron boiler that is very beefy, take a look at the Peerless 63 series. It only goes down to 88,000 input, so it is oversized unless you need some extra capacity for an indirect. Thermal efficiency is supposed to be around 82%. I will probably installing one of those in my home when it is time and will run it with steam if I pull out the hot water system. I'll gain some additional efficiency with the steam by getting rid of the circ pump even though I'll lose about 1% on the thermal efficiency side. If I can find an appropriate heat exchanger, I could probably go into condensing mode since the return temps on the steam system I will be putting in will be around 75 or 85 F most of the year, but then will need to go power vent, so the electrical will probably eat up much of the fuel savings.